More than one million birds to be destroyed as bird flu is detected at a seventh Victorian farm

Chickens will be euthanased to try to stop the spread of the avian influenza. (ABC Danielle Bonica)

Australia's largest outbreak of bird flu has hit a grim milestone, with Victorian authorities confirming more than one million birds will be killed to try and prevent the spread of the virus.

Seven farms across south-west Victoria have now been found with highly pathogenic strains of avian influenza, affecting hundreds of thousands of farmed birds.

The outbreak began on an egg farm near Meredith in May, and has continued to spread in the region as local farmers face the harsh reality of Australia's biosecurity response to outbreaks of emergency animal diseases.

Victoria's chief veterinary officer, Graeme Cooke, said the latest infected farm housed between 150,000 and 200,000 egg-laying chickens.

"This latest infected premises was once again picked up on very early surveillance and that means it can be dealt with very early," Dr Cooke said.

"I really thank producers within the restricted area where all the cases have been for their help and collaboration as we work our way through this outbreak."

Nation's largest outbreak

The death toll from the current outbreak of bird flu is more than double the state's most recent outbreak in 2020, which resulted in the death of over 400,000 birds, including emus, turkeys and chickens, across the state.

The current outbreak is concentrated mostly to the Golden Plains Shire, one of the largest regions that produces eggs and chicken meat in Victoria, producing about a quarter of Victoria’s eggs.

A control zone is in place spanning approximately 100 kilometres from west to east across the region, covering six of the seven farms detected with the H7N3 strain of avian influenza.

"[Control measures] really reduce the level of virus in an area. The faster we can pick it up, the less risk there is of onwards spread," Dr Cooke said.

"The requirements in the controlled areas, especially the restricted areas, are to prevent onward movement of the virus either by vehicles, people or other means.

"Meredith has consistently been detecting [bird flu].

"If this virus was allowed to spread onward it would be devastating for the rest of the poultry industry in Victoria and perhaps onward through Australia.

"The right thing to do is to stop the infected premises being any further risk, and that's the action that is taken through the humane destruction and disposal and the onwards cleansing and disinfection of the farms."

An egg farm near Terang was also found to have bird flu within its chicken population last month, however authorities found a different strain, H7N9.

Agriculture Victoria is investigating the cause of the outbreaks but so far it is believed the disease has spread from wild birds into domestic poultry.

Duck farm infected

The state's outbreak of avian influenza has also spread to a commercial duck farm near Meredith.

Australian Duck Meat Association CEO Greg Parkinson said the farm represented about two per cent of Australia's commercial duck population and mostly supplied meat to restaurants, not supermarkets.

"It was not unexpected, it's a smallish duck farm — about 40,000 birds — and it was very close to the infected egg farms," he said.

"Ducks are kept in sheds precisely for these sorts of reasons — we try to buffer ourselves from wild bird incursions and virus spillovers.

"About 30 million ducks are processed for meat per year."

Australia's duck meat industry is relatively concentrated and run by two main processors, Luv-a-Duck, which has about 30 farms in western Victoria, and Pepe's Ducks which runs out of New South Wales.

The infected duck farm does not supply either of these companies.

International infections

There are many types of bird flu, including the highly pathogenic H5N1 strain, which has been detected in Asia, Europe, the Middle East, Africa, North America, South America and Antarctica.

This strain of the disease has spread beyond poultry, affecting various mammals including penguins, cattle and humans.

This strain has not been detected in Australian animals, however the nation recorded its first ever human case in March, when a child returned home from India with the disease.

The child has since recovered and authorities have confirmed there is no ongoing threat to the public.

Australia's response to eradicate avian influenza is in stark contrast to countries like the United States, where more than 96 million birds have been affected by the disease since an outbreak that began in 2022, according to the U.S Centre for Disease Control and Prevention.

Anyone who notices abnormal behaviour in their flocks, or unexplained deaths, is urged to contact the 24-hour Emergency Animal Disease Watch Hotline on 1800 675 888.